This invention relates to power supply systems, and more particularly, to cable television (CATV) amplifier power supply redundancy.
Communication systems are used to transmit and deliver information to consumers in a variety of ways. These systems include satellite, cellular, and wireline networks and the information can be virtually anything, from analog to digital and incorporating telephony, video, data, etc. Due to signal losses inherent in the transmission of signals over great distances, amplifiers are often necessary to boost the signal level. The amplifiers ensure that signals are at the proper power level as they pass through and out of the network. Maintaining the signals at a constant power level is important for many systems, such as cable television systems. Further, a loss of power can be devastating to service providers.
Cable television (CATV) systems provide content to subscribers, typically by routing signals from a satellite to a subscriber utilizing communication systems such as fiber optic cables and/or coaxial cables. FIG. 1 shows an example of a cable television system 10 including a satellite 12 transmitting signals to a headend 14 that receives and demodulates the signals to baseband. The baseband signal is transmitted over the communication system after conversion to an optical signal or a radio frequency. As illustrated, a fiber optic system 16 transports the optical signal to a hub 18 and then onto a node 20. Amplifiers 22 are normally utilized in the system to increase signal levels. Taps 24 are inserted in the communications system 10 to deliver the signals to subscribers 26.
CATV amplifiers are an important part of the overall CATV system. Constant power should be provided to these amplifiers at all times. Typically, the node 20 has redundant power sources assuring they are never without power in the event of a failure of one of the power supplies. However, the amplifiers do not have a redundant power source. Further, if redundant power was available to amplifiers, keeping the power supplies synchronized would be a challenge.
A master/slave configuration can be utilized to regulate power supplies with one power supply configured to control the other power supply or power supplies. Conventional power supply master/slave configurations involve power supplies operating in parallel with one power supply preset as the master and one as the slave. Power levels can be maintained by sensing output currents. However, in the event of a failure, conventional systems do not provide automatic redundancy where one power supply is automatically selected as the master and the other as the slave.
Accordingly, a need exists for systems and methods for efficiently providing redundant power to CATV amplifiers and for automatically selecting one power supply as the master power supply and one as the slave power supply.